<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            height: 2000px;
        }

        .box1 {
            /*position: relative;*/
            /*position: absolute;*/
            position: fixed;
            top: 0;
            left: 0;
            width: 200px;
            height: 200px;
            background-color: red;
        }

        p {
            height: 100px;
            background-color: #a827e3;
        }

        .big {
            /*position: relative;*/
            height: 300px;
            background-color: #2a8293;
        }
    </style>
</head>
<body>
<p></p>
<div class="big">
    <div class="box1"></div>
</div>

</body>
</html>
